Biomedical subjects

C Sanders

Publications and source records attributed to C Sanders.

At least 19 recordsLinked to original sources

PubMed2004

Coping with bladder exstrophy: diverse results from early attempts at functional urinary tract surgery.

OBJECTIVES: To report the long-term surgical outcome in a group of patients with bladder exstrophy treated from 1960 to 1982, and to assess physical health, social integration and sexual function, as attempts at functional closure during the development of this surgery resulted in patients with differing surgical status of the genitourinary organs. PATIENTS AND METHODS: A review of medical record archives revealed 36 patients; of these, seven had died, six were untraceable and six declined to participate, leaving 15 evaluable subjects (seven men and eight women, mean age at follow-up, 35 years). Data were collected from medical records and direct interviews were conducted using a semi-structured questionnaire, after obtaining informed consent. The Short Form-36 (SF-36) v2 Health Survey instrument was used to assess health and well-being. RESULTS: Three patients have retained the use of their bladder, and 11 had initial bladder closure but required (at a mean age of 3.1 years) various urinary diversions. Eight patients had a pelvic osteotomy. Of 27 functioning renal units, 25 are in reasonable to good condition. Six men and six women had genital reconstruction. Four men are capable of penetrative intercourse and ejaculate; six women manage penetrative intercourse and five have orgasms. All patients attended mainstream school and 13 achieved examination success. Nine patients took vocational training and 11 work full-time. Five patients are married and five are in long-term relationships. Two men have achieved three pregnancies and one women has had a child. The mean total SF-36 score (maximum 3600) was 2763 in men and 2235 in women. CONCLUSIONS: Surgery for bladder exstrophy has been developing for more than 40 years and the legacy of early attempts at functional closure is a population of adults who have a diversity of lower urinary tracts, good preservation of renal function overall and acceptable sexual function. They are usually robust, healthy and well-adjusted individuals functioning well in society, often in full-time employment and long-term relationships. Adolescent follow-up must be clearly focused, incorporating a multidisciplinary team approach to facilitate a seamless transition into adulthood.

Adaptation, Psychological↗

PubMed2004

High sensitivity scanning of colorectal tumors and matched plasma DNA for mutations in APC, TP53, K-RAS, and BRAF genes with a novel DHPLC fluorescence detection platform.

Tumor-associated DNA has been detected in plasma of colorectal cancer (CRC) patients using various techniques but with limited gene or mutation coverage. We report a highly sensitive scanning methodology for mutational assessment of the APC and TP53 genes, which typically pose an analytical challenge because of their significant genotypic heterogeneity as well as specific mutational scoring assays for K-RAS and BRAF. Plasma DNA isolated from 20 CRC patients were scanned for mutations in these targets without knowledge of the molecular or pathological analyses of the matched primary tumors. We chose mutation scanning technology and these molecular targets to provide a comprehensive screen for somatic mutations known to be associated with sporadic CRC. Mutations were identified with a novel denaturing high-performance liquid chromatography (DHPLC) platform that uses post-separation fluorescence technology to enable the detection of variants that represent <0.1% of the total analyzed DNA. Mutant allele specific amplification (MASA) followed by detection with the same platform was used to identify low-level target mutations (mutation scoring) in K-RAS codons 12, 13, and 61, and BRAF codon 599. Using this combined scanning and scoring approach, we were able to identify at least one mutational event in 20/20 (100%) CRC patients. The thoroughness of a mutation scanning and scoring panel may have important implications for CRC screening and disease monitoring during and following therapy.

Alleles↗

PubMed2003

Unmet need for joint replacement: a qualitative investigation of barriers to treatment among individuals with severe pain and disability of the hip and knee.

OBJECTIVE: To explore barriers to health-care utilization in respondents with moderate to severe hip/knee symptoms of pain and disability. METHODS: In-depth interviews were carried out with 27 participants who had high levels of hip/knee pain and disability (according to New Zealand scores). There were 10 men and 17 women; median age 76 yr (range 51-91). The data were analysed thematically using the constant comparison technique. RESULTS: Three types of barrier were identified: (i) people's own perceptions of need and reluctance to seek treatment, (ii) perceptions and experiences of primary care and (iii) experiences of treatment in secondary care. Pessimism about availability of treatments, and concerns about effectiveness and risks of surgery, made older people reluctant to seek medical help. Such views were often confirmed by GPs. Some of those referred to a hospital specialist were told that they were too young or too mobile for surgery. CONCLUSION: Barriers to treatment and unmet need for joint replacement exist in the UK, particularly amongst older people.

Age Factors↗

PubMed2002

The anocutaneous reflex and urinary continence in children with myelomeningocele.

OBJECTIVE: To examine the hypothesis that because most patients with myelomeningocele and a positive anocutaneous reflex have a competent sphincteric mechanism they are more likely to be continent on intermittent catheterization than those with a negative reflex, and to become so with less need for adjunctive surgical treatment. PATIENTS AND METHODS: The study included 111 patients with myelomeningocele treated for urinary incontinence; their present means of treatment and the outcome achieved were assessed and related to the presence or absence of an anocutaneous reflex. RESULTS: Among 29 patients with a positive anocutaneous reflex, 26 (90%) are currently dry on a regimen of intermittent catheterization, as opposed 41 (50%) of the 82 with a negative reflex (P < 0.001). Two (7%) of those with a positive and 23 (28%) of those with a negative reflex have undergone adjunctive surgery (P=0.024). CONCLUSION: These findings are consistent with both aspects of the hypothesis detailed in the Objective.

Adolescent↗

PubMed2001

Generation of high quantities of viral and tumor-specific human CD4+ and CD8+ T-cell clones using peptide pulsed mature dendritic cells.

CD4+ and CD8+ T cells are key components of immune response against tumors and viruses. Many techniques have been used to clone and expand these cells in vitro for purposes of immunotherapy. Here, we describe an improved method to obtain large quantities of tumor and virus-specific human CD4+ and CD8+ T-cell clones. T cells derived from peripheral blood mononuclear cells (PBMCs) of healthy donors were stimulated several times by peptide pulsed monocyte-derived mature dendritic cells (DCs) in the presence of exogenous cytokines. T cells specific for influenza or melanoma antigens were detected by IFN-gamma intracellular staining and were cloned by limiting dilution. Specific polyclonal T-cell populations were derived for all epitopes presented by mature DCs. Nine different populations were cloned and clones were raised from eight of them. Clonality was verified by HLA/peptide tetramer staining. With additional rounds of stimulation after the cloning procedure, it was possible to obtain from 10(9) to 10(12) of each clone. Furthermore, clones could be maintained in culture in the presence of IL-2 for at least 1 month without losing their antigen-specific reactivity (e.g. cytokine secretion, cytolytic activity and proliferation). Importantly, a majority of the CD8+ T-cell clones recognized endogenously processed antigens. This method is of value for the purposes of adoptive anti-virus or anti-tumor immunotherapy.

Amino Acid Sequence↗

PubMed2001

Efficiency of cross presentation of vaccinia virus-derived antigens by human dendritic cells.

Dendritic cells (DC) utilize at least two pathways to process viral antigens onto MHC class I molecules. The conventional endogenous route is used to acquire antigens from both infectious and non-replicating virions. Exogenous pathways are used by DC to acquire and "cross-present" antigens derived from virus-infected donor cells that by themselves lack the ability to activate T cells directly. We analyzed the role of this pathway for antigens derived from vaccinia, a virus which inhibits DC maturation and causes extensive apoptosis of infected cells, yet is highly immunogenic. Using recombinant vaccinia virus encoding the influenza matrix protein as model vector, DC were shown to cross-present vaccinia-derived antigens from both apoptotic and necrotic infected cells to antigen-specific CD8(+) T cells. Efficient cross presentation required uptake of dead cells by immature DC and exposure to maturation stimuli, especially CD40 ligand. The responding CD8(+) T cells secreted IL-2 and IFN-gamma, proliferated and developed into cytotoxic effectors. Quantification of the cross presentation of vaccinia-derived antigens showed this pathway to be highly efficient, corresponding to a peptide pulse of 10-100 nM. While monocytes also phagocytosed apoptotic and necrotic cells, they were far less efficient at cross-presenting vaccinia-derived antigens to CD8(+) T cells. The ability of DC to cross-present vaccinia-derived antigens from infected apoptotic cells or necrotic cell lysates, bypasses the deleterious effects of direct infection of DC and provides one explanation for this pathogen's immunogenicity.

Antigen Presentation↗

PubMed2001

Transport of cytochrome c derivatives by the bacterial Tat protein translocation system.

An experimental system developed previously for the heterologous expression of c-type cytochromes in Escherichia coli Q1has been adapted to monitor protein transfer across the bacteria's cytoplasmic membrane. Apocytochrome, lacking the haem cofactor and probably in an unfolded state, was readily transferred across the cytoplasmic membrane when fused to a Sec-specific signal peptide. Furthermore, cytochrome fused to a signal peptide regarded as specific for the twin arginine transport (Tat) system was translocated in an unfolded state by the Sec apparatus. After maturation and folding in the cytoplasm, Tat-mediated transfer of holocytochrome to the periplasm occurred. We conclude that, in addition to the nature of the specific signal peptide, the folding state of a particular protein also governs its acceptance by a given transport system.

Amino Acid Sequence↗

PubMed2001

Bileaflet aortic valve prosthesis pivot geometry influences platelet secretion and anionic phospholipid exposure.

The clinical histories of the Medtronic Parallel (MP) and St. Jude Medical (SJM) Standard valves suggest pivot geometry influences the thrombogenic characteristics of bileaflet prostheses. This work studied the effects of various pivot geometries on markers of platelet damage in a controlled, in vitro apparatus. The Medtronic Parallel valve, two St. Jude Medical valves, and two demonstration prostheses were used to study the effects of bileaflet pivot design, gap width, and size on platelet secretion and anionic phospholipid expression during leakage flow. A centrifugal pump was used to drive blood through a circuit containing a bileaflet prosthesis. Samples were taken at set time intervals after the start of the pump. These samples were analyzed by cell counting, flow cytometry, and enzyme-linked immunosorbant assay. No significant differences were observed in platelet secretion or anionic phospholipid expression between experiments with the SJM 27 Standard regular leaker, the SJM 20 regular leaker, and the MP 27 valves. Significant differences in platelet secretion and anionic phospholipid expression were observed between a SJM 27 Standard regular leaker and a SJM 27 high leaker valve. These studies suggest that leakage gap width within bileaflet valve pivots has a significant effect on platelet damage initiated by leakage flow.

Anions↗

PubMed2001

Children with autism display more social behaviors after repeated imitation sessions.

Based on earlier studies, an adult's imitations of the behaviors of children with autism lead to increased social behavior in the children. The present study explored the effects of repeated sessions of imitation. Twenty children were recruited from a school for children with autism to attend three sessions during which an adult either imitated all of the children's behaviors or simply played with the child. During the second session the children in the imitation group spent a greater proportion of time showing distal social behaviors toward the adult including: (1) looking; (2) vocalizing; (3) smiling; and (4) engaging in reciprocal play. During the third session, the children in the imitation group spent a greater proportion of time showing proximal social behaviors toward the adult including: (1) being close to the adult; (2) sitting next to the adult; and (3) touching the adult. These data suggest the potential usefulness of adult imitative behavior as an early intervention.

Attention↗

PubMed2001

Adolescent depression and risk factors.

Seventy-nine high school seniors were administered the Center for Epidemiological Studies Depression Scale (CES-D), as well as a questionnaire on parent relationships, peer relationships, positive and negative feelings including suicidal thoughts, and lifestyle variables including academic performance, exercise, and drug use. The group of adolescents who scored above the clinical cutoff for depression on the CES-D (n = 29) had poorer relations with parents. Further, the incidence of paternal depression in that group was greater. The depressed adolescents also had less optimal peer relationships, fewer friends, and were less popular. They experienced less happiness and more frequent suicidal thoughts. They spent less time doing homework, had a lower grade point average, and spent less time exercising. The depressed group also reported more use of marijuana and cocaine. A stepwise regression indicated that physical affection with parents, homework, well-being, exercise, happiness, and parent relations explained 55% of the variance.

Adolescent↗

PubMed2001

Nutrition: impact on oral and systemic health.

Good dietary practices and optimal nutritional status promote growth and tissue development, as well as feature prominently in the prevention of diseases. Malnutrition (particularly protein-energy malnutrition, which invariably involves concurrent deficiencies of the antioxidant micronutrients) promotes salivary gland hypofunction, impaired immunity, and an early shift in the oral microbial ecology toward a preponderance of anaerobic organisms. The immune suppression, which includes impaired cytokine function as well as diminished acute-phase response to infections, impacts negatively on the natural history of inflammatory periodontal diseases. The pathogenesis of oral cancer is influenced by deficiencies of antioxidant nutrients, and there is evidence for diminished DNA methylation, disruption of DNA integrity, and increased DNA damage in folate deficiency.

Acute-Phase Reaction↗

PubMed2000

Expression of prokaryotic and eukaryotic cytochromes c in Escherichia coli.

C-type cytochromes from various sources show substantial structural conservation. For the covalent attachment of heme groups to apocytochromes, however, three different enzyme systems have been described so far. We have examined the ability of the heme ligation systems of Escherichia coli and of Saccharomyces cerevisiae to process cytochromes from S. cerevisiae, Paracoccus denitrificans, and Synechocystis sp. PCC 6803. E. coli's maturation system with at least eight different proteins accepted all these cytochromes for heme ligation. The single subunit heme lyase from S. cerevisiae mitochondria, on the other hand, failed to attach heme groups to cytochromes of prokaryotic origin.

Apoenzymes↗

PubMed2000

Biomaterial engineered electrodes for bioelectronics.

A series of single-cysteine-containing cytochrome c, Cyt c, heme proteins including the wild-type Cyt c (from Saccharomyces cerevisiae) and the mutants (V33C, Q21C, R18C, G1C, K9C and K4C) exhibit direct electrical contact with Au-electrodes upon covalent attachment to a maleimide monolayer associated with the electrode. With the G1C-Cyt c mutant, which includes the cysteine residue in the polypeptide chain at position 1, the potential-induced switchable control of the interfacial electron transfer was observed. This heme protein includes a positively charged protein periphery that surrounds the attachment site and faces the electrode surface. Biasing of the electrode at a negative potential (-0.3 V vs. SCE) attracts the reduced Fe(II)-Cyt c heme protein to the electrode surface. Upon the application of a double-potential-step chronoamperometric signal onto the electrode, where the electrode potential is switched to +0.3 V and back to -0.3 V, the kinetics of the transient cathodic current, corresponding to the re-reduction of the Fe(III)-Cyt c, is controlled by the time interval between the oxidative and reductive potential steps. While a short time interval results in a rapid interfacial electron-transfer, ket1 = 20 s-1, long time intervals lead to a slow interfacial electron transfer to the Fe(III)-Cyt c, ket2 = 1.5 s-1. The fast interfacial electron-transfer rate-constant is attributed to the reduction of the surface-attracted Fe(III)-Cyt c. The slow interfacial electron-transfer rate constant is attributed to the electrostatic repulsion of the positively charged Cyt c from the electrode surface, resulting in long-range electron transfer exhibiting a lower rate constant. At intermediate time intervals between the oxidative and reductive steps, two populations of Cyt c, consisting of surface-attracted and surface-repelled heme proteins, are observed. Crosslinking of a layered affinity complex between the Cyt c and cytochrome oxidase, COx, on an Au-electrode yields an electrically-contacted, integrated, electrode for the four-electron reduction of O2 to water. Kinetic analysis reveals that the rate-limiting step in the bioelectrocatalytic reduction of O2 by the integrated Cyt c/COx electrode is the primary electron transfer from the electrode support to the Cyt c units.

Biocompatible Materials↗

PubMed2000

Developmental and light-dependent regulation of a phloem-localised K+ channel of Arabidopsis thaliana.

K+ channels in plants can currently be classified into six families with individual members being involved in nutrient uptake, loading of the xylem and the physiology of stomatal movement. In this study we have focused on akt2/3. This K+ channel, as shown by GUS-expression analysis, is expressed in the phloem and xylem of the aerial parts of Arabidopsis thaliana. Northern blot analyses revealed the highest akt2/3-concentrations in the flower stalk, followed by the leaf, flower and stem. During the light period (8 am to 4 pm), transcripts reached a peak around noon (11 am), decayed to almost 50% in the afternoon and reached a low background level in the following dark period. In continuous darkness, however, the K+ channel mRNA content had already decreased beyond the background level by noon. In leaves and flower stalk, the light-induced transcription of akt2/3 was suppressed by CO2-free air, indicating that gene activity is under the control of photosynthates. Additionally, when rosette leaves were illuminated and flower stalks shaded, akt2/3-mRNA transcription was still inhibited in the shaded region. This indicates that channel gene activation is sensitive to photosynthesis-derived factors from neighboring cells rather than factors mobile in the phloem. We propose that the coupling between sugar production and allocation involves the photosynthate- and light-dependent phloem K+ channel AKT2/3.

Arabidopsis↗

PubMed2000

Age-associated changes in the immune system of German shepherd dogs.

In order to look into the ageing of the canine immune system we investigated age-related changes and associated gender-related differences in parameters of innate and acquired immunity in German Shepherd dogs. We obtained the following findings: white blood cell counts, peripheral blood lymphocytes, lymphocyte proliferative activity and interleukin-2 (IL-2) serum concentrations were significantly lower in the group of old animals, whereas the concentrations of gamma-globulins and the functional activity of the complement system were significantly higher in the elderly. Phagocytic and bactericidal activity of polymorphonuclear cells, as well as their 'killing function,' the serum cytokine-like activities of tumour necrosis factor-alpha and the plasma concentrations of immunoglobulin G, as well as of alpha- and beta-globulins, were not significantly affected by age, whereas natural killer-cell activity and the serum cytokine-like activities of IL-1 were significantly higher only in the group of female old animals. With regard to gender-related differences, lymphocyte proliferative activities as well as plasma concentrations of alpha-globulin were significantly higher in the group of female animals, whereas the absolute numbers of segmented neutrophils were significantly lower. Species analogies with regard to ageing as presumed to exist between man and laboratory rodents also seem to be applicable to the dog. The observed age-related changes in the canine immune system are probably among the main causes for the multimorbidity of old age, affecting life expectancy and mortality in the dog and should be recognized and considered by the attending veterinarian.

Aging↗

PubMed2000

Aortic dissection with intimal intussusception: diagnosis and management.

A man presented with acute chest and back pain with loss of consciousness. CT scan showed a mass in the arch that extended into the descending aorta. A diagnosis of type I aortic dissection was ultimately made by echocardiography. At surgery there was a circumferential intimal tear in the aortic root, and an intussuscepted dissection flap was retrieved from the arch and descending aorta.

Aortic Dissection↗

PubMed1999

Certification in infection control and epidemiology-a celebration of 15 years!

Certification in infection control has been available since 1983. In this, the 15th anniversary of the Certified in Infection Control examination, it seems appropriate to examine how the program was developed, how it has evolved, and future opportunities for Certification in Infection Control and Epidemiology. This article was written to provide a brief history and an update on the current status of the Certified in Infection Control program.

Certification↗

PubMed1998

Reporting on quality of life in randomised controlled trials: bibliographic study.

OBJECTIVES: To examine the frequency and quality of reporting on quality of life in randomised controlled trials. DESIGN: Search of the Cochrane Controlled Trials Register 1980 to 1997 to identify trials from all disciplines, from oncology, and from cardiovascular medicine that reported on quality of life. Assessment of abstracts from articles published from 1993 to 1996. Assessment of a sample of full reports with a standardised instrument. MAIN OUTCOME MEASURES: Prevalence of reporting on quality of life. Conditions and interventions studied in trials reporting on quality of life. Quality of reporting on quality of life. RESULTS: During 1980-97 reporting on quality of life increased from 0.63% to 4.2% for trials from all disciplines, from 1.5% to 8.2% for cancer trials, and from 0.34% to 3.6% for cardiovascular trials. Of 364 abstracts, 65% reported on drug interventions. Of a sample of 67 full reports, authors of 48 (72%) used 62 established quality of life instruments. In 15 reports (22%) authors developed their own measures, and in 2 (3%) methods were unclear. Response rates were given in 38 (57%), and complete reporting on all items and scales occurred in 31 (46%). CONCLUSIONS: Less than 5% of all randomised controlled trials reported on quality of life, and this proportion was below 10% even for cancer trials. A plethora of instruments was used in different studies, and the reporting of methods and results was often inadequate. Standards for the measurement and reporting of quality of life in clinical trials research need to be developed.

Data Collection↗